S. D(X) = 6 and S. D(Y) = 8. If X and Yare independent random variables, then S. D(X-Y) is:

14

Explanation:

For independent variables X and Y;

S.D(X - Y) is expanded as :

S.D(X) + S.D(Y)

If S.D(X) = 6 and S.D(Y) = 8 ; where, X and Y are independent ;

SD(X-Y) = SD(X) + SD(Y)

SD(X - Y) = 6 + 8

SD(X - Y) = 14

i think that the correct answer is

c. p equals 5,000 times, 0.3, to the power of the fraction m over 20